1. Field of the Invention
The present invention relates to an optical coupling structure optically coupling a plurality of cores mutually and an optical fiber amplifier.
2. Description of the Related Art
In case of using a multi-core optical fiber in which a plurality of cores are disposed in a cladding, there is a case that an optical functional component such as an optical isolator or an optical filter etc. is inserted between two multi-core optical fibers. In addition, in case that a multi-core optical fiber has an optical amplification function, there is a case that an optical component inputting pumping light into the multi-core optical fiber is inserted between two multi-core optical fibers (for example, see Japanese Laid-open Patent Publication No. H10-125988 or P. M. Krummrich and Klaus Petermann, “Evaluation of Potential Optical Amplifier Concept for Coherent Mode Multiplexing”, OFC2011, OMH5.).